Faculty Publications
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Item Ag-TiO2 nanoparticles for photocatalytic degradation of lomefloxacin(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Kulkarni, R.M.; Malladi, R.S.; Hanagadakar, M.S.; Doddamani, M.R.; Bhat, K.U.The photocatalytic activity of silver-doped TiO2 (Ag-TiO2) nanoparticles was studied by photocatalytic degradation of lomefloxacin (LMF) using a photoreactor with a mercury lamp (PHILIPS, TUV 8 W T5, Emax = 254 nm). The 1 and 2% silver-doped TiO2 nanoparticles were synthesized by liquid impregnation (LI) method. The resulting nanoparticles were characterized by surface analytical methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray analysis and transmission electron microscope (TEM). The study shows 2% Ag-TiO2 nanoparticles exhibited better results (95% degradation) in 1 h for the degradation of lomeofloxacin compared to 1% Ag-TiO2 and pure TiO2. XRD analysis indicated that the crystallite size of TiO2 was 17.00 nm, while the crystallite size of 1% Ag-TiO2 and 2% Ag-TiO2 was 13.07 to 14.17 nm. TEM images show the particle size of Ag-TiO2 nanoparticles were in the range 40–45 nm in length and 10–15 nm in breadth. Pseudo-first-order rate constants were found to decrease with increase in pH. The effect of UV intensity, catalyst dosage and initial concentration of LMF on the degradation rate were also studied and elaborately discussed. © 2015 Balaban Desalination Publications. All rights reserved.Item Acetaminophen micropollutant: Historical and current occurrences, toxicity, removal strategies and transformation pathways in different environments(Elsevier Ltd, 2019) Vo, H.N.; Le, G.K.; Nguyen, T.M.; Bui, X.-T.; Nguyen, K.H.; Rene, E.R.; Vo, T.D.H.; Cao Ngoc, N.-D.; Mohan, R.Acetaminophen (ACT) is commonly used as a counter painkiller and nowadays, it is increasingly present in the natural water environment. Although its concentrations are usually at the ppt to ppm levels, ACT can transform into various intermediates depending on the environmental conditions. Due to the complexity of the ACT degradation products and the intermediates, it poses a major challenge for monitoring, detection and to propose adequate treatment technologies. The main objectives of this review study were to assess (i) the occurrences and toxicities, (2) the removal technologies and (3) the transformation pathways and intermediates of ACT in four environmental compartments namely wastewater, surface water, ground water, and soil/sediments. Based on the review, it was observed that the ACT concentrations in wastewater can reach up to several hundreds of ppb. Amongst the different countries, China and the USA showed the highest ACT concentration in wastewater (?300 ?g/L), with a very high detection frequency (81–100%). Concerning surface water, the ACT concentrations were found to be at the ppt level. Some regions in France, Spain, Germany, Korea, USA, and UK comply with the recommended ACT concentration for drinking water (71 ng/L). Notably, ACT can transform and degrade into various metabolites such as aromatic derivatives or organic acids. Some of them (e.g., hydroquinone and benzoquinone) are toxic to human and other life forms. Thus, in water and wastewater treatment plants, tertiary treatment systems such as advanced oxidation, membrane separation, and hybrid processes should be used to remove the toxic metabolites of ACT. © 2019 Elsevier LtdItem Enhanced disinfection of E. faecalis and levofloxacin antibiotic degradation using tridoped B-Ce-Ag TiO2 photocatalysts synthesized by ecofriendly citrate EDTA complexing method(Springer Science and Business Media Deutschland GmbH, 2022) Sekar, P.; Sadanand Joshi, D.; Manjunatha, M.; Mahalingam, H.Since its use for photochemical water splitting reported first in 1972, TiO2 is one of the most extensively studied photocatalysts for a diverse range of applications. Monodoping or codoping of the catalyst is a proven strategy to enhance the functionality of TiO2 under solar or visible light. However, the use of three or more dopants in the development of more efficient and visible light active photocatalysts has not been investigated widely, especially for microbial disinfection. Boron/cerium/silver tridoped TiO2 photocatalysts with curated amounts of the dopants (B = 1, 2 at.%, Ce = 0.1 at.%, Ag = 0.06 at.%), synthesized by the ecofriendly EDTA-citrate method, were evaluated for the disinfection of water using Enterococcus faecalis under UV-A irradiation and degradation of levofloxacin antibiotic under solar light. The catalyst characterization revealed that the spherical nanoparticles had a crystallite size of ~ 13 nm and bandgap energy values of 2.8–2.9 eV. 2B-0.1Ce-0.06Ag-TiO2 is the best catalyst for microbial disinfection with a log reduction and kinetic rate constant ~ 30 and ~ 4.5 times higher than those values determined for the other codoped or monodoped catalysts, confirming an enhanced performance. Regarding levofloxacin degradation, the best performing catalyst is 1B-0.1Ce-0.06Ag-TiO2 with degradation of 99% and 83% COD reduction in 100 min. The tridoped photocatalysts are very effective in the inactivation of Enterococcus faecalis, thus solving the problem of antimicrobial resistance in waters containing antibiotic residues. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Adsorption of selective fluoroquinolones by cysteine modified silane magnetic nanocomposite from the aqueous phase(Institute for Ionics, 2023) Senathiraja, T.; Lolla, S.A.; Singh, Y.; Kollarahithlu, S.C.; Mohan Balakrishnan, R.M.Elevated levels of pharmaceutical pollutants in the aquatic environment have caused detrimental effects on water quality and biodiversity. Nanomaterials are among the most promising technologies to detect, adsorb, and remove these pollutants from the aqueous systems. The current work explores the applicability of nickel ferrite nanocomposite functionalized with L-cysteine attached 3-glycidyloxypropyltrimethoxysilane to remove a selective class of antibiotics known as fluoroquinolones (Lomefloxacin, Ciprofloxacin, and Norfloxacin). 20 mg of this nanocomposite achieve maximum removal efficiencies of 61%, 67%, and 75% for 40 mg L−1 of lomefloxacin, norfloxacin, and ciprofloxacin, respectively. The nanocomposites also show good regeneration capacity with negligible reduction in the efficiencies up to three cycles. Furthermore, adsorption isotherms such as Langmuir and Freundlich isotherms were used to characterize the removal of fluoroquinolones from the aqueous phase by the nanocomposites. The results show that the adsorption process was in good agreement with the Langmuir isotherm, thus confirming its monolayer sorption process and also reveals that adsorption kinetics follows a pseudo-second-order model. The maximum adsorption capacity of functionalized nickel ferrite nanocomposites are 122 mg g−1, 135 mg g−1, and 150 mg g−1 for lomefloxacin, norfloxacin, and ciprofloxacin, respectively. Overall, all the results obtained indicate that the nickel ferrite nanocomposite functionalized with L-cysteine attached 3-glycidyloxypropyltrimethoxysilane is an effective adsorbent to remove fluoroquinolones from the aqueous systems and could be potentially incorporated in water treatment processes under well-defined parameters. © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.Item Photocatalytic Degradation of Chlorpyrifos and Tetracycline in Aqueous Medium Using Silver Titanate Perovskite Nanoparticles(Springer Science and Business Media Deutschland GmbH, 2024) Joseph, A.; Raval, K.; Manirethan, V.Near-infrared (NIR) active silver titanate perovskite (AgTiO3)-based photocatalysis is a potential method for degrading organic pollutants due to its unique structural features, compositional flexibility, and affordability. Herein, we have synthesized novel NIR-active AgTiO3 nanoparticles with a low band gap of 0.92 eV via the hydrothermal method using Ananas comosus leave extract, which is a major agricultural waste worldwide. The produced AgTiO3 nanoparticles were characterized using Fourier Transform Infrared (FTIR) spectroscopy investigations, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy dispersive X-ray spectroscopy (EDS). The photocatalytic activities of the AgTiO3 nanoparticles toward the degradation of tetracycline and chlorpyrifos under UV, visible, NIR, and solar light irradiation were carefully examined, and the photocatalytic mechanism was proposed using liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography (HPLC). AgTiO3 nanoparticles completely degraded tetracycline and chlorpyrifos within 27 min and 21 min, respectively. The increased efficiency of AgTiO3 nanoparticles produced by green synthesis over conventional photocatalysts points to a potential advancement avenue for water treatment systems. Furthermore, using agricultural waste like leftover pineapple leaves not only lessens the impact on the environment but also solves the issue of cost when putting these technologies into practice on a larger scale. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.